The use of multiwell filtration plates is well established in the life sciences. They have been used among things as microtiter plates, cell growth plates, drug candidate screening tools and high throughput systems for the recovery of DNA, RNA, SEQ products, proteins, peptides and the like.
They all encompass the same basic design features. There is a plate having a series of two or more wells, each well having an open top and a open bottom that is essentially closed in some manner, except for an outlet and a filter positioned at or above the outlet and sealed in a manner such that all fluid to filtered must pass through the filter before reaching the outlet. Typically a collection plate is positioned below the filtration plate to collect the filtrate.
These devices are of a few basic designs.
The first being where the well bottom is open and a filter is sealed across the bottom of the well to make a semipermeable outlet. Often an underdrain is attached below the filter and contains a series of spouts that direct the filtrate into the collection plate. See U.S. Pat. No. 4,902,481.
A second version takes a bottom insert or short plate having a series of two or more wells an open top and an essentially closed bottom except for an outlet and a top plate having a corresponding series of wells having an open top and an open bottom and a filter piece positioned between the two. The two plates are formed together into one integral unit be it by thermal bonding or by injection molding one of the plates to the other. See U.S. Pat. No. 4,948,442 or U.S. Pat. No. 6,391,241.
The third version is to form a single piece multiwell device having a series of two or more wells having an open top and an at least partially to substantially closed bottom and inserting a filter piece into each well and securing it at or near the bottom by a separate ring such as a gasket (See U.S. Pat. No. 5,116,496) or by heat sealing the filter to the bottom of the well (See U.S. Pat. No. 6,309,605).
All of these devices use some type of external pressure to cause the filtration, be it a positive pressure, generated by centrifugation or a positive pressure (higher than atmospheric) applied to the top of the wells or a vacuum applied to the bottom of the wells below the outlet.
These plates have typically been arranged in rows and columns where each row and each column is parallel to the all the other rows or columns respectively and perpendicular to the intervening columns and rows respectively.